The Kidney in the Shadow of Cirrhosis: A Critical Review of Renal Failure.

Hepatorenal syndrome (HRS) is a high-mortality, potentially reversible form of kidney failure that arises from a tight hemodynamic-inflammatory coupling in cirrhosis. Contemporary redefinitions prioritize creatinine kinetics over static thresholds and recognize non-acute kidney injury (AKI) functional phenotypes, enabling earlier recognition but heightening the need for precise etiologic triage. This narrative synthesis integrates current concepts across pathophysiology, diagnosis and management. Portal hypertension, bacterial translocation and inflammatory mediators amplify splanchnic vasodilation and effective arterial underfilling. Compensatory neurohumoral activation precipitates renal vasoconstriction, intrarenal microcirculatory dysfunction and sodium-water retention. The pivotal diagnostic fork remains HRS-AKI versus acute tubular necrosis. A pragmatic, tiered strategy, structured volume assessment, filtration markers and a parsimonious tubular-injury panel offer actionable discrimination, whereas fractional excretion indices serve as adjuncts only. Initial therapy should be bundled and time-sensitive: remove nephrotoxins, treat infection and initiate albumin plus a vasoconstrictor. The transplant strategy should default to isolated liver transplantation unless end-stage renal disease is established. Future priorities include validated biomarker cut-offs, ultrasound-guided volume algorithms and pathway-based trials to reduce diagnostic delay and improve survival.